/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.android.common.logger;

/**
 * Helper class for a list (or tree) of LoggerNodes.
 *
 * <p>
 * When this is set as the head of the list, an instance of it can function as a
 * drop-in replacement for {@link android.util.Log}. Most of the methods in this
 * class server only to map a method call in Log to its equivalent in LogNode.
 * </p>
 */
public class Log {
	// Grabbing the native values from Android's native logging facilities,
	// to make for easy migration and interop.
	public static final int NONE = -1;
	public static final int VERBOSE = android.util.Log.VERBOSE;
	public static final int DEBUG = android.util.Log.DEBUG;
	public static final int INFO = android.util.Log.INFO;
	public static final int WARN = android.util.Log.WARN;
	public static final int ERROR = android.util.Log.ERROR;
	public static final int ASSERT = android.util.Log.ASSERT;

	// Stores the beginning of the LogNode topology.
	private static LogNode mLogNode;

	/**
	 * Returns the next LogNode in the linked list.
	 */
	public static LogNode getLogNode() {
		return mLogNode;
	}

	/**
	 * Sets the LogNode data will be sent to.
	 */
	public static void setLogNode(LogNode node) {
		mLogNode = node;
	}

	/**
	 * Instructs the LogNode to print the log data provided. Other LogNodes can
	 * be chained to the end of the LogNode as desired.
	 *
	 * @param priority
	 *            Log level of the data being logged. Verbose, Error, etc.
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 * @param tr
	 *            If an exception was thrown, this can be sent along for the
	 *            logging facilities to extract and print useful information.
	 */
	public static void println(int priority, String tag, String msg, Throwable tr) {
		if (mLogNode != null) {
			mLogNode.println(priority, tag, msg, tr);
		}
	}

	/**
	 * Instructs the LogNode to print the log data provided. Other LogNodes can
	 * be chained to the end of the LogNode as desired.
	 *
	 * @param priority
	 *            Log level of the data being logged. Verbose, Error, etc.
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged. The actual message to be
	 *            logged.
	 */
	public static void println(int priority, String tag, String msg) {
		println(priority, tag, msg, null);
	}

	/**
	 * Prints a message at VERBOSE priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 * @param tr
	 *            If an exception was thrown, this can be sent along for the
	 *            logging facilities to extract and print useful information.
	 */
	public static void v(String tag, String msg, Throwable tr) {
		println(VERBOSE, tag, msg, tr);
	}

	/**
	 * Prints a message at VERBOSE priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 */
	public static void v(String tag, String msg) {
		v(tag, msg, null);
	}

	/**
	 * Prints a message at DEBUG priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 * @param tr
	 *            If an exception was thrown, this can be sent along for the
	 *            logging facilities to extract and print useful information.
	 */
	public static void d(String tag, String msg, Throwable tr) {
		println(DEBUG, tag, msg, tr);
	}

	/**
	 * Prints a message at DEBUG priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 */
	public static void d(String tag, String msg) {
		d(tag, msg, null);
	}

	/**
	 * Prints a message at INFO priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 * @param tr
	 *            If an exception was thrown, this can be sent along for the
	 *            logging facilities to extract and print useful information.
	 */
	public static void i(String tag, String msg, Throwable tr) {
		println(INFO, tag, msg, tr);
	}

	/**
	 * Prints a message at INFO priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 */
	public static void i(String tag, String msg) {
		i(tag, msg, null);
	}

	/**
	 * Prints a message at WARN priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 * @param tr
	 *            If an exception was thrown, this can be sent along for the
	 *            logging facilities to extract and print useful information.
	 */
	public static void w(String tag, String msg, Throwable tr) {
		println(WARN, tag, msg, tr);
	}

	/**
	 * Prints a message at WARN priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 */
	public static void w(String tag, String msg) {
		w(tag, msg, null);
	}

	/**
	 * Prints a message at WARN priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param tr
	 *            If an exception was thrown, this can be sent along for the
	 *            logging facilities to extract and print useful information.
	 */
	public static void w(String tag, Throwable tr) {
		w(tag, null, tr);
	}

	/**
	 * Prints a message at ERROR priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 * @param tr
	 *            If an exception was thrown, this can be sent along for the
	 *            logging facilities to extract and print useful information.
	 */
	public static void e(String tag, String msg, Throwable tr) {
		println(ERROR, tag, msg, tr);
	}

	/**
	 * Prints a message at ERROR priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 */
	public static void e(String tag, String msg) {
		e(tag, msg, null);
	}

	/**
	 * Prints a message at ASSERT priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 * @param tr
	 *            If an exception was thrown, this can be sent along for the
	 *            logging facilities to extract and print useful information.
	 */
	public static void wtf(String tag, String msg, Throwable tr) {
		println(ASSERT, tag, msg, tr);
	}

	/**
	 * Prints a message at ASSERT priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param msg
	 *            The actual message to be logged.
	 */
	public static void wtf(String tag, String msg) {
		wtf(tag, msg, null);
	}

	/**
	 * Prints a message at ASSERT priority.
	 *
	 * @param tag
	 *            Tag for for the log data. Can be used to organize log
	 *            statements.
	 * @param tr
	 *            If an exception was thrown, this can be sent along for the
	 *            logging facilities to extract and print useful information.
	 */
	public static void wtf(String tag, Throwable tr) {
		wtf(tag, null, tr);
	}
}
